The preparation and measurement of antibodies with a high degree of specificity for human malignant tumor-associated antigens will be continued using a variety of cell lines that have been accumulated and established in culture. The specificity and binding characteristics of a variety of monoclonal antibodies prepared at this laboratory will be studied in detail. They will be compared with purified polyclonal antibodies to the same cell lines. Polyclonal antibodies will be purified using cellular immunoadsorbents. Immunoadsorbents made with monoclonal and polyclonal purified antibodies will be employed to isolate and identify melanoma-associated antigens derived from allogeneic melanoma cells. Studies will include solid phase target cells assays and the use of radiolabeled antibodies. Antigens isolated from lysates of surface labeled melanoma cells will be incubated with antibodies and immunoprecipitates will be analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Melanoma-associated antigens also will be transferred from polyacrylamide gels to nitrocellulose paper ("Western blotting") and located using specific antibodies and radiolabeled staphylococcal protein\A. Antisera produced in various ways will be screened this way for antibodies directed towards antigens prepared from different melanoma cells. Characterized antigens will be used to develop new radioimmunoassays, to induce antisera with high specificity and may lend themselves for diagnostic and therapeutic purposes.